High-tension underground cable



- HAYMAN HIGH TENSION UNDERGROUND CABLE Filed Oct. 25, 1927 BELT [v.suLAT/ON.

Inventor: William C. I". ayman.

b M JfjZ y H is Attorney Patented Aug. 14, 1928.

- :nrurse qsr a.

WILLIAM c. HAYMAN; F SCHENECTADY,

NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIG- COItFEANY, -A -'COR-PORATIONOF NEW YORK.

: The; present invention relates to multiple .conductor hightensionunderground cable .and has for its object to provide fillers therefor,of. improved construction to, the end that gas-.ma y be,excludeclflifromithe. interior of m che claims appended .theretO- e: ebles omp etyis ib s ib ei- I a i e ider 'e pfi atl li e be novel; andinyention, attention ;is dit e he eq pa y es es r ptiee a Iri a t sts?!dewie ski l ie fi i estiatir set; my eve t ni show n ere-asse i oe-a reeeesli t tb etle a ,I Qe he pi rp 's I t i s sa i e ly u r t- 4 e y er smiIrhere ai we- .nection with af25 QQO u three;conducter cable but it 'isnot to; understood as limited 7 thereto or to I the, man ing shape fof\thefconductors altl ioughthe arrangement of the latter isparticularlyadvantageous"in ,acablelofthiseharacter i Each fofa centralconductor mernber' l whic'h is segmental in cross section, and snuglysurrounding it is a plurality of sniallenconductors 2 which are laid upin any suitable way so that the conductor as a whole is self-supporting.Surrounding each of the conductors thus formed are numerous layers ofinsulation 3, said layers being composed for example of relativelynarrow, tightly-wound strips or ribbons of tough paper, the jointbetween adjacent strips in one layer being covered by other strips bothabove and below it. The conductors are assembled in a we lknown mannerto form a body in which they are spaced 120 apart. Surrounding theconductors and their individual lnSlll l tions is an annular covering orbelt of insulation 4 which may also be formed of paper and wound on inthe manner described for the individual conductors. Outside of the beltinsulation is a lead sheath 5.

Between the conductors thus assembled both at the center and adjacentthe belt insulation are spaces 6 in which are located fillers. It is tothe construction of these fillers that my invention is specificallydirected. The commonly accepted arrange ment is to make these fillerswholly of jute in the form of relatively hard twisted cords or to makethem wholly of paper. Both of these are objectionable because thematerial does not properly pack. Owing to the fact that the places wherethe insulating HIGH-TENSION UNDERGROUND C ABLE.

' ,Ap uifio'n filed October 25, 1527., serial No. 228,646.

covering and' the belt insulation contact wedge-shapedspaces or openingsare formed and to the fact that the jute cords are round and ofconsiderable size they do not prop- .erlyz fillj the spaces and as aresult. small. voids are'formed in which gas can and does collect witliitheresult that ionization takes place 'in' these regions. When paperalone is uujsedf'it also fails completely fill the s'paces between; theconductor coverings due wholly orii large part to the lack of resil ieney;o 't hefpape'rf I fovercom e'the: objection above noted by using a,filler which is composed of three distinctfelement-s instead of one. Thesides .of each filler .where the space. between the beltjand conductorcove 'ings contracts to the proportions of a knife edge as indicated at7, areiee'mposedhof paper strios 8 and for purposcl have found kraftpaper to be .sat1sfactory. The. paper is cut into relative ly wid n'trips and is passed through a suitmachine.whichcrumples it and at theiisamejtime' gives to it a wedge-like formation 11i crpss-sectionand ofany, sui able length.

The paper may take the form of a paper cord or twine and be given thewedge-like formation as the conductors are passe through a forming orsizing die in the cable assembling operation. Between two of thesewedge-like strips is located a suflicient number of jute cords 9, tofill the remainder of the space. The number of these cords and the sizethereof will vary for different size cable as will be readilyappreciatei'l. Since the jute cords are somewhat elastic they serve tofirmly press the side. paper members laterally into the wedge-likeopenings with the result of completely filling the spaces betweenconductor coverings and the belt insulation. For the central spacebetween the conductors I also employ a filler of crumpled kraft paper 10which in the assembling operation made to completely fill the centralregion between them. For this purpose it is preferable to use a numberof pieces of paper cord or twine which extend lengthwise of the cableand the pressure of the sizing or forming die squeezes the paper to theshape indicated.

F or simplicity of description, I have referred to the fillers in thepositions they occupy aft-er the cable parts are assembled. In makingthe cable each of the conductors is first insulated, then they are laidup or asscmbled with,.the central tiller between them, and the paperand'jute fillers in the outer spaces. The conductors and the fillers arethen passed through a sizing die-which compresses them, after 11Whi0hthe belt insulaton is tightly wound thereon. The cable is thenthoroughly impregnated With-asuit able compound, as heayy oil, ,forexample,

in any suitable manner, after which thelead sheath is applied. Due tothe elasticity of the jute the'paper wedges or members are forcedlaterally, which action is in part due to the sizing die and the.wound-on'belt insulatlon and the paper, and completely fill thewedge-like portions of the filler spaces. Any iuinu te spaces} or voidsare filled with the compound or fiuidwith which the paper insulation andthe fillers are impregnated.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is; 1. In a cable, the combination of a number ofseparately-insulated conductors, a belt of insulation which surroundsthe conductors and bindsl them together,'and fillers for the 1 spacesbetween the conductor coverings and the belt insulation, each of whichcomprises side members'which are made of paper and a central memberlocated between the side members and which is made of jute.

2. In a cable, the combination of a number of separately-insulatedconductors," a wrapping of paper whichforms:the be1t insulation andbinds the conductors together, and fillers for the spaces between theconductors and the belt insulation, each of which comprises two sidemembers which are made of kraft paper and are wedgeshaped incross-section and a central member located between the side memberswhich 'lation and'fillers, and a fluid-tight metallic sheath whichencloses the belt insulation.

4. In a cable, the combination of a number of separately-insulatedconductors, a body of paper located within the space defined by thecontacting surfaces of the conductorwinsulations and filling the same, abelt of insulation which surrounds the conductors and binds themtogether, and fillers for the spaces defined by the conductorinsulations and the belt insulation, each of said fillers comprisingwedge-shaped side members madeof paper and a member centrally locatedbetween the side members and made of jute, said jute exerting side-wisepressure on the paper members.

In witness whereof, I have hereunto set my hand this 24th day ofOctober, 1927.

WILLIAM C. HAYlVLAN

